In general, a local network, which is a local area network, refers to a network for processing or transmitting information generated by various communication terminals or information processing terminals including a host computer or a work station installed in a limited area, such as a building and a factory, by using wired or wireless resources.
LIPA Mobility and SIPTO at the Local Network (LIMONET, hereinafter, referred to as an “extended local network”), which is an example of the local network, may be referred to as an extended network architure of a Local IP Access and Selected IP Traffic Office (LIPA-SIPTO).
The extended local network aims to support session continuity in the local network considering mobility between femto cell base stations (H(e)NB) installed in a home network or a company network and provide a traffic offload function, which has been considered in a macro network, even in the local network.
For example, the extended local network suggests the direct transfer of data traffic of a User Equipment (UE) accessing through the H(e)NB to other devices at home or a company network through a Local-Gateway (L-GW), not transferring the data traffic to a core network that is a network of a mobile communication service provider.
FIG. 1 illustrates an example of a structure of a conventional extended local network, in which an H(e)NB and an L-GW are unified and jointly operated. Hereinafter, the extended local network having the structure in which the H(e)NB and the L-GW are unified and jointly operated is called a “collocated local network”.
H(e)NB 106 and L-GW 104 coexisting in the collocated local network illustrated in FIG. 1 may be determined as a single logical and/or physical entity 102, and the H(e)NB 106 and the L-GW 104 exchange information through internal interfaces.
Accordingly, a UE 100 may exchange information with other IP devices 108 through the H(e)NB 106 and the L-GW 104 configuring the single entity 102. For example, a user packet provided from the UE 100 to the H(e)NB 106 is transferred to the L-GW 104 through an internal interface and the user packet transferred to the L-GW 104 is provided to other designated IP devices 108.
However, the collocated local network illustrated in FIG. 1 has an advantage of a simple structure, but its structure has a difficulty in satisfying the mobility of the UE.
FIG. 2 illustrates an example of a structure of a conventional extended local network considering mobility, in which an H(e)NB and an L-GW are separated from each other. That is, FIG. 2 defines that the H(E)NB and the L-GW may be separated and independently configured. Hereinafter, the extended local network having the structure in which the H(E)NB and the L-GW are separated is called a “stand-alone local network”.
Respective stand-alone local H(e)NB networks 210 and 220 in FIG. 2 may be defined as a set of H(e)NBs 214, 216, and 218, or 224 and 226 connectable to local PDNs 230 and 240 through one or more L-GWs 212 and 222 by a unique IP address. In this case, the L-GW 212 or 222 belongs to only one stand-alone local H(e)NB network 210 or 220, and may access by the one or more PDNs 230 and 240.
In a technical report concerning the stand-alone local H(e)NB network, requirements for a scenario and a structure for a continuity of a Selected IP Traffic Office (SIPTO) session according to mobility and movement in a local network are defined. In addition, the technical report includes the stipulation of main issues and a structure for a solution for satisfying the requirements for the structure, L-GW selection and addressing, a discovery of a region for a Local IP Access (LIPA), an LIPA deactivation, etc.
However, all solutions for supporting the stand-alone local H(e)NB network have not been prepared yet, so that a method of solving a significant issue which has been discussed in relation to the existing stand-alone local H(e)NB network is urgently required. Especially, it is necessary to prepare a method of supporting a session continuity based on mobility of the UE in the stand-alone local H(e)NB network.
In addition, since a user may be free to buy and install or remove the H(e)NB 206 or the L-GW 204 in the local network, method of the H(e)NB and the L-GW discovering each other and making a connection there between in a dynamic configuration is required.